Purification of water.



UNITED STATES. PATENT OFFICE.

HEINRICH KRIEGSHEIM, 0F BERLIN, GERMANY, 'ASSIGNOR TO THE PERMUTIT.

COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

PURIFICATION or WATER.

No Drawing.

To all whom it may concern Be it known that I, HEINRICH KRrEos- HEIM, a citizen of the German Empire, residing at Berlin, in Germany, have invented certain new and useful Improvements in Purification of vWater, of which the follow-. ing is a specification.

This invention relates to the purification of water; and it comprises a method of purifying water wherein such water is treated with a free halogen, such as chlorin, (or with a chlorin-yielding substance, such as hypochlorite). is filtered over or through a pervious or minutely porous material, or over or through a material consisting of or comprising an oxid of a metal having two or morestates'of oxidation, such as the oxid of iron, of nickel, of cobalt, of manganese, of cerium, of lead, etc. and adapted -to catalyze conversion of such free halogen into other bodies; such minutely pervious material being advantageously a zeolite or zeolitic ma-.

terial of natural or artificial origin and such zeollte also advantageously comprislng one or more such oxid; all as more fully hereinafter set forth and as claimed.

Chlorin has long been used for antiseptic and disinfectantpurposes, and of late it has also been gaining favor as ameans of sterilizing potable water. For this purpose chlorin is sometimes used as such, the gas or trolysis of a' chlorid solution, are emto the water.

ployed, the electrolyzed solution being added For the present purposes the three ways are equivalents, since, in accord ance with well understood reactions, the final results in high dilution of a chlorin solution or a hypochlorite'solution are much the same. As to whether the active agent in sterilization is chlorin itself, hypochlorous acid or oxygen, is not here important.

Instead of chlorin, and chlorin evolving compounds, other halogens, are sometimes employed. Bromin and hypobromates are used, especially for field purposes; and. iodin is also sometimes used.

Chlorin and chlorin-evolving ,prepara Specification of Letters Patent.

Patented Sept. 12, 1916.

Application filed August 11, 1914. Serial No. 856,284.

tions are extremely active sterilizing agents,

effectually killing all the bacteria and other organisms of water. Even a highly contaminated water after addition of a surprising small amount of chlorin is rendered safe from a sanitary point of view. Chlorin however has nosubstantial purifying power in water apartfrom its lethal value in killing organisms; it does not affect turbidity or hardness or lessen the dissolved solids. Nor,

ployed in the exact amount necessary; the

amount corresponding to the chlorin-absorbing power of the bacteria and other organic matters present. Naturally, amounts less than this cannot be safelyv employed. Y It is therefore always used in some excess, that is, there is always more chlorin put into the water than can be absorbed and converted by the organic matter present. This. excess of chlorin however. is a source of considerable difficulty since it does not tend to disappear rapidly at common temperatures and in the absence of sunlight. In chlorin-sterilization therefore elaborate measures must always be taken to get rid of this necessary excess; as by aerating the water, allowing it to rest in shallow pools, etc. The necessity for this after-treatment has militated against the use of chlorin, advantageous-as such use would otherwise appear. I

For a number of hours after a chlorin treatment, this excess of chlorin (or its 'oxy: gen compounds) can readily be detected in the water. For one thing there is always .a chlorin .taste? which many people find highly objectionable, Water containing chlorin or hypochlorite is also quite corrosive on metal service pipes and fittings. I have found however that I can obtain all the advantages of chlorin sterilization without these disadvantages by employing a sin":

ple after-treatment which consists in rapidly passing the treated water through or over materials of minutely pervious nature; as by filtering it through or trickling it over such materials. Conversion of the chlorin (or. hypochlorous acid) into harmless and non-noticeable substances is rapid and com plete. For this purpose it is. best to employ materials which while completely pervious- (being for instance dyed throughout by sponding thereto can usually be completely" taken up by the amount of bases present in most waters or those added, as'in using bleaching powder, eau de Javelle, etc. The chlorids-formed, in this dilution, of course cannot be detected by the taste.

The reactions by which the chlorin disappears may be represented en u pirically,-

Ol a-H O HClO-l-HCl HClO-l-catalyst HC1+Q In the first reaction chlorin is converted by hydrolysis into hypochlorous *and hydrochloric acids. The hypochlorous acid is catalyzed into hydrochloric acid and oxygen by the catalyst. The oxygen disappears by oxidation of the organic matters which are always present. The hydro chloric acid in turn disappears by union with the lime and magnesia compounds which are also always present, forming harmless and, in this dilution, tasteless calcium and magnesium chlorids. Where bleaching powder is used as a sterilizing agent calcium compounds are, of course, always present. The best materials I have found for this purpose are the substances known as zeolites or exchange silicates, of natural or artificial origin arid now in common use for softening water. These zeolites are made as miiiutely pervious granules having the power of softening hard water by exchanging the soda they contain for dissolved lime or magnesia. After use they are revivified by treatment with a salt solution which takes up the lime or magnesiaor both and replaces it or them inthe zeolite with soda. I have found that these zeolites have also an extraordinary catalytic power in removing dissolved chlorin as such from water, the Water passing'through a bed evincing no further reaction for, or taste of, free chlorin even with rapid filtration. The amount of total chlorin (that naturally present and that added in sterilization) is the same in the water passing to present purposes.

this dilution is tasteless.

The same effect of rapid and complete acid may be attained by the use of catalytic oxids of metals having more than one stage of oxidation, such as the oxids of lead, iron, cerium, nickel, copper, cobalt, etc. The higher oxids of these metals catalyze the conversion of chlorin and hypochlorous acid into other bodies, harmless for the The action does not change the oxid save in that if the original material contain the lower oxids they are at once converted into the higher. Only minute or catalytic quantities of these oxids are necessary. They are also best used in a minutely pervious condition since the action here, as in the case of zeolites, is a surface phenomenon; a phenomenon depending, to

a large degree, upon the surface exposed to the water. For this reason where the oxids are used as such they are best used inconnection with a porous carrier; being for example precipitated on or in such a material as pumice stone, kieselguhr, etc. While the general action of these oxids in quickly converting free chlorin or hypochlorous acid is the same, the action difl ers in detail'and this difference may be utilized in modifying the' present process for various purposes. With manganese and iron oxids, the oxygen liberated in the reaction of chlorin with water appears as ozone or hydrogen peroxid.

removal of free chlorin or hypochlorous With oxids of lead, cerium, copper, nickel or cobalt the oxygen appears as ordinaryoxygen; and, on the other hand, these oxids have the power of destroying ozoneor hydrogen peroxid which may occur in the water, either as ,a result of the chlorin treatment or as a result of an after treatment with manganese oxid. They also, of course have the power of destroying dis solved ozone or hydrogen peroxid which may gain access to the waterin other ways' as in sterilizing with ozone or peroxid. Another variation of my method, particu larly advantageous for slightly turbid, im-

pure water, consists in developing permanganic acid or permanganates (formed with the bases present) therein at the expense of the residual chlorin. For this purpose the zeolite and that passing beyond; but the eflluent contains neither free chlorin nor hypochlorites. The use of these zeolites offers the convenience that sterilization by the chlorin-containing water is first transmitted through a mixture of nickel and manganese oxids. This results in a violet color in the liquid, due to the formation of permanganic acid. -The resulting flocculation and formation of manganese oxids by the oxidation of organic matter by the permanganate (which is avery quick and energetic oxidizer) carries down turbidity. Any residual permanganic acid may be. remoied by filtrationover reduced manganese OX1 s.

. responding amount of lime, or soda, as the case may be. Materials of this character may be readily prepared by treating ordinary artificial or other zeolites with the chlorids or other salts of the particular metal which is to be used. For example,

by filtering a dilute solution of nickel chlorid through an ordinary zeolite the latter may be caused to take up any desired amount of nickel existing as a base 1n combination with alumina and silica and replacing a corresponding amount of soda or lime. Cobalt zeolite, manganese zeolite, iron zeolite, cerium zeolite, copper zeolite, etc., may be prepared in this way. For a lead zeolite, it is best to use lead acetate or nitrate. These zeolites may be used in thesame way as that described for the oxids; and work much more eflectually for the same amount of oxid since, in effect, a relatively small amount of oxid may be thereby given a relatively enormous surface of exposure to the water.

Where a water contains dissolved com- I pounds of oxidizable oxids such as manganese or iron bicarbonate, the previously described methods allow their easy and rapid removal since the catalytic conversion of the free chlorin at the same time accelerates enormously the oxidation of these oxids which, otherwise, would take .place only relatively slowly. With such waters, simple pervious bodies, such as the ordinary zeolites, are sufficient, though of course oxidcontaining zeolites may also be used.

For removal of free chlorin, of hypochlorous acid, of ozone and of hydrogen peroxid, the nickel-containing zeolite is ,upon the whole the best material.

Any of the described. methods may be applied to water which has been treated with the other halogens, bromin or 'iodin, with hypobromates or with iodates.

In one advantageous embodiment of the present invention I utilize the high disinfecting and oxidizing power of ozone. As stated, while chlorin is an active lethal agent for micro-organisms its oxidizing action is As will be perceived, in the methods just often not so rapid as can be desired; and particularly with waters containing much organic matter. With these waters, ozone is a more vigorous and rapid oxidant. Therefore in this embodiment of my inyention I take water which has been treated with chlorin or other halogen and which still contains residual halogen, and pass it through a manganese zeolite in the manner previously described. This results in the formation of ozone or hydrogen p roxid in the water. This ozone is allowed: 0 exert its action on the water for a time and then the water is sent through a filter containing .a cobalt or nickel zeolite, or cobalt or nickel oxid. Nickel oxid or nickel zeolite is particularly advantageous. This now breaks up any residual ozone or hydrogen peroxid, with evolution of free oxygen.

The whole process may be continuous, the water containing chlorin, hypochlorite, etc., being sent first through a filter containing oxidized manganese zeolite (a zeolite containing higher manganese oxids) then allowed to-flow through a conduit of large cross section to give a certain amount of time for interaction between the ozone and the organic matter and thence being sent through a filter bed of nickel zeolite. As

stated, the zeolites may also be used for softening the water at the same time.

While 1 have particularly described this invention as applicable to the treatment of water treated with halogens such as chlorin,

or their oxids, it may also be applied to the treatment of waters containing ozone. The use of ozone for purifying water has become somewhat general, but, like chlorin, a portion of the ozoneis apt to remain in the water treated, imparting to it a rough taste which is not liked, the property of corroding pipes, etc.

The exchange silicates and the oxids stated have the same converting action upon ozone that they have upon chlorin and other halogens, causing it to disappear rapidly and completely from water sentthrough or over such silicates or oxids What I claim is 1- 1. The process of treating water which comprises sterilizing the same with-chlorin and thereafter filtering over minutely pervious silicate material 2. The process of treating water which comprises sterilizing the same with a halo gen and thereafter filtering over minutely pervjous silicate material. I

3. The process of treating water which comprises sterilizing the same with a halogen and thereafter filtering over an exchange silicate. 4. The process of treating water which comprises sterilizing the same with chlorin and thereafter filtering over an exchange silicate.

comprises sterilizing the same with a halogen and thereafter filtering over an exchange silicate containing an oxid of a metal having two stages of oxidation.

7. The process of treating water which comprises sterilizing the same with chlorin and thereafter filtering over an exchange silicate containing nickel oxid. i

8. In the treatment of water, the process which comprises sterilizing such water with chlorin and thereafter filtering over minutely pervious material comprising an oxid of a metal having two stages of oxidationv and in the higher state of oxidation.

9. In the treatment of water the process which comprises sterilizing such water with a halogen and thereafter filtering over minutely pervious material comprising an oxid of a metal having two stages of oxidation and in the higher state of oxidation.

10. In the treatment of water, the process which comprises sterilizing such water with chlorin and thereafter filtering over minutely pervious material comprising oxid of nickel.

11. In the purification of water the process which comprises treating such water with a halogen filtering the treated water over minutely pervious material comprising manganese oxid. and thereafter filtering over material comprising nicket oxid.

12. The process of purifying water which comprises treating the water with a halogen, filtering such water over material comprisinga catalytic oxid capable of replacing the excess of halogen by an actively oxidizing oxygen-containing substance and then removing such substance by filtration over material comprising another catalytic metal oxid.

13. In the purification of water the process which comprises treating such water with a halogen, filtering the treated water over silicate material comprising manganese oxid and thereafter filtering over silicat material comprising nickel oxid.

14. The process of purifying water which comprises treating the water with chlorin, filtering the treated water over an exchange silicate comprising a catalytic oxid capable of replacing an excess of chlorin by an actively oxidizing oxygen containing sub-- stance and then removing such substance by a further filtration of the treated water over an exchange silicate comprising an other catalytic metal oxid.

In testimony whereof, I affix'my signature in the presence of two subscribing witnesses.

HEINRICH KRIEGSHEIM.

Witnesses J l G. TALMAon, BRENNAN B. Wns'r. 

